Hot-air furnace



(No Model.) 2 Sheets-Sheet 1.

J. BiOLDE-RSHAW. HOT AIR FURNAGE.

N0. 449,693. Patented Apr. 7, 1891.

WITNESSES: INVENTOR:

ATTORNEY.

(No Model.) I 2 Sheets-Sheet 2.

' J. B. OLDERSHAW.

HOT AIR FURNACE.

No. 449,693. Patented Apr. 7, 1891.

mum yilllllll WITN INVENTOR:

ATTORNEY.

UNITED STATES PATENT OFFICE.

JOHN B. OLDERSHAW', OF BALTIMORE, MARYLAND.

HOT-Al R FU RNAC E.

SPECIFICATION forming part of Letters Patent No. 449,693, dated April'7, 1891.

Application filed July 26, 1890- Serial No. 359,995. (No model.)

To aZZ whom it may concern:

Be it known that 1, JOHN B. OLDERSHAW, a cltizen of the United States,residing at Baltimore, in the State of Maryland, have invented certalnncwand useful Improvements in Hot- Air Furnaces, of which the followingis' a specification.

This invention relates to a furnace for produclng hot air for heatinghouses.

The invention is designed to avoid the diffusion of heat within thecellar or room where the furnace may be set.

The invention is shown in the accompanying drawings, in which Figure 1is a side elevation of the furnace. F g. 2 1s a central vertical sectionof same. Fig. 3 is a horizontal section of the furnace on the line 3 3.Figs.4 and 5 are also horizontal sections on lines 4 4 and 5 5,respectively.

The letter A designates the fire pot and combustion-chamber; b, thegrate; c, a top plate, and d a draft-regulating plate below the topplate.

Q designates an outer jacket or case, and C an inner jacket between thewalls of the combustion-chamber and the outer jacket. These two acketsor cases form two annular spaces D D around the combustion-chamber. Theouter case 0 extends, as usual, from the base E to the covered top F butthe inner case 0' commences at the top of the ash-pit G, wheresupporting-brackets e are secured. This inner case rests on thesebrackets and therefrom extends upward to atop deflecting-plate H, whichextends above and partly covers the combustion-chamber and has a largecentral opening f.

The base E has air-inlets g g, which allow cold air to enter the twoannular spaces D D. The annular space D next to the combustion-chamberwill contain the hottest air and the outer annular space D will containair more or less heated, but not heated as highly as the other. Thecovered top has a central cone-shaped depression h, the lowest point ofwhich comes down toward the central opening fin the deflecting-plate H.Hot-air-conveying pipes I are attached to the top at a point above theinside deflecting-plate H. By this construction of parts air will enterthe baseinlets g g, and the current will divide and parts will pass upeach of the two spaces D D.

That which passes up the inner space D will come against the topdeflecting-plate H, and thereby will be forced over the top plate 0 ofthe combustion-chamber toward the center opening f of saiddeflectingplate, through which it will pass up into the top space It,where it will meet the. other current of heated air that passes up theouter space D. The two currents will commingle in the top space is andthen pass to the pipes I. These two separate spaces D D' maintain so lowa temperature of the outer case 0 as to prevent the diffusion of heattherefrom into a cellar or room where the furnace is set up.

The draft-regulating plate d, below the top plate 0 of thecombustion-chamber, has indirect openings Znear its perimeter, whichlead up to a gas-chamber J, which is divided into compartments by meansof the vertical deflecting-plates n n. This plate 01 also has a directopening m near or under a dome 0 on the top plate 0, with which dome asmoke pipe N connects. A damper m, between the plates n n, guards thedirect opening, and a rod m operates the damper. When the damper m isclosed, the products of combustion will have to pass through theindirect openings Z, which are near the hot wall of thecombustion-chamber, and into the top chamber J, and then to the dome 0and smoke-pipe N. This indirect route of passage serves, first, to morehighly heat the products of combustion before reaching the gas-chamberJ, and, second, it afiords time for the heat of these products to beabsorbed. by the top plate 0, which latter then diffuses it or gives itoff to the air-currents.

The door 19 guards the feed-passage q, and the door 0" a passage 3 on alevel with the grate, through which the poker may be in serted.

Having described my invention, I claim-- 1. A hot-air furnace having, incombination, the combustion-chamber A, a jacket or case 0, surroundingsaid chamber and leaving an annular space D between, an outer jacket orcase 0, surrounding thejacket first mentioned and leaving an annularspace D between, a top deflecting-plate H, forming a close connectionwith the said inner jacket and which extends above and partly covers thecombustion-chamber, and a covered top F, closely connected with the saidouter jacket and having a central cone-shaped depression h, the lowestpoint of which comes down toward the central opening in thedeflecting-plate, as set forth.

2. Ahot-airfurnace having, in combination,

the combustion-chamber, the top of which is provided with a gas-chamberhaving direct and indirect openings thereto from the combustion-chamber,deflecting-plates in the gaschamber forming communicating compartmentstherein, a smoke-pipe communicating with one of the compartments, and adamper in that chamber for guarding the direct opening therein,substantially as described.

